Storage transfer samples need full integration tests

[theacodes]

The current tests for the storage transfer service mock everything, which isn't very useful in terms of ensuring the sample still works with the live API.

We need to come up with a plan to test these. The only one that might be difficult is the AWS one, as it will require us to have an AWS account.

[theacodes]

I'm closing this for now, it doesn't seem feasible to test these right now.